In a single capstan type cassette tape recorder in which a magnetic tape is held between a single capstan and a pinch roller to be fed, the magnetic tape is controlled in its travelling position by a tape guide provided on a side wall of a magnetic head and is in good contact with the magnetic head by means of the pad provided in the cassette to resiliently urge the magnetic tape against the magnetic head.
However, in a dual capstan type cassette tape recorder in which the magnetic tape is held between two capstans and two pinch rollers facing these capstans, respectively, that portion of the magnetic tape positioned between the two sets of a capstan and a pinch roller has a tension and a travelling position provided thereto. Therefore, if the magnetic tape is resiliently urged against the magnetic head by the pad in the cassette, then a back tension of the magnetic tape portion provided by the two sets of capstans and pinch rollers cannot be effectively provided, and the travelling position of the magnetic tape cannot be maintained at the front face of the magnetic head because the pad tends to urge the magnetic tape in an unstable manner. Also, a tape guide positioned between the capstans tends to damage the magnetic tape due the displacement of the tape guide.
In general, in case a cassette is used in a digital tape recorder, with a pad in the cassette being composed of felt or the like, an unstable tension tends to be disadvantageously applied to the magnetic tape because the pad of felt tends to be affected by temperature and moisture. U.S. Pat. No. 3,777,070 discloses the provision of pad spacer means on a magnetic head for keeping the pad spaced from the magnetic head. This avoids the aforementioned drawback. In this U.S. patent, upper and lower sections of the spacer means are disposed apart by a distance generally equal to a width of a magnetic tape and have respective shoulders provided to engage the edges of the magnetic tape so as to guide it. However, if such pad spacer means are used in a dual capstan type cassette tape recorder, it is quite difficult to make a travelling position of the magnetic tape coincident with a tape guide position provided by the shoulders of the spacer means. If the tape travelling position is even slightly displaced relative to the tape guide position, the magnetic tape will be damaged by being forcefully guided. Thus, it will be noted that it is not proper to use the spacer means of U.S. Pat. No. 3,777,070 in a dual capstan type tape recorder.
On the basis of the aforementioned prior art, it will be easily understood that the abutting members are provided merely with a recess positioned adjacent to the front face of the magnetic head in order to avoid damage to the magnetic tape due to engagement of the abutting members with the magnetic tape. However, the distance between the abutting faces of the abutting members and the front face of the magnetic head is difficult to determined with precision, and in case that the abutting members are formed of resilient metal plate, the abutting members tend to be deformed due to their abutment against the pad and an external force applied thereto. This causes the magnetic tape to be damaged because the abutting members contact the upper or lower edge of the magnetic tape.